…and the zoologists will come. As the quote goes ”You build it, and they will come (1)” it’s not difficult to picture the scene of a newly built green roof, where three fully equipped biologists pop up from nowhere, even before the animals could find it.
There is always something moving about finishing a work that kept you busy for a period of time. No doubt, it is even more moving when we translate our work into numbers. Last year we only told a story. Now we provide the research frame and a short list just to sum up the season:
Problem: Surface of urban green roofs increases each year, but our knowledge of their role on local animal diversity is far from satisfactory. Yes, we assume these roofs are “important”, but it’s unclear why, and how important they are in Finland?
Goal: Discovering the current fauna of vegetated roofs of similar age in Helsinki-Vantaa area, reveal conservation values and potential threats (alien/invasive species), as well as the main drivers of invertebrate community compositions.
Methods: Vacuum insect collector (DVac122) and colour pan traps, so we don’t harm the roof material.
Who: Ferenc Vilisics PhD, Kukka Kyrö, PhD student, Henri Järvisalo summer intern, and Susanna Lehvävirta, principal of the “Fifth Dimension” research programme.
When: May-August 2012
Emptying the sample mesh bag of the DVac
The numbers (without mentioning the endless list of meetings, consultations and informal chats):
- Visited 21 roofs in 10 addresses,
- Visited each roof 4 times between May and August.
- Driven cc. 600 km by car, used cc. 42 l of gasoline.
- Spent roughly 20 full days on the roofs, and devoting cc. 380 man-hour for the task.
- Collected cc. 1080 DVac samples, operated DVac for cc. 500 minutes (8h 30mins).
- Used cc. 20 rolls of 3–5L plastic bags and 4 liters of gasoline for DVac-ing.
- The team members have climbed the ladders cc. 130 times altogether.
- Injuries: zero, but ripped one trousers.
The work went as it has been planned without any major events. After a somewhat shaky start on a cold and windy day of May, we could eventually develop our routine enabling us great efficiency and made each move predictable.
“Louie, I think this is the beginning of a beautiful friendship”(2). Yes, indeed. The vacuuming is just the beginning of a long bitter-sweet assignment in the lab, selecting all the bugs from 1080 samples. One average sample contains over 100 microscopic mites, springtails and thripses, but samples with 500 specimens aren’t rare either.
I am not a particularly brave person, but for most people – perhaps - a green roof research may relate to courage. I have a good deal of acrophobia (horror of height), plus allergic to bee sting. Courage, however, is not the most important feature one needs in the pursuit of better understanding urban green roof ecology. It’s more like curiosity.
Curiosity overcomes impossible conditions – evidence provided by generations of students and supervisors working in the field and labs 24/7 just to get answer to even the most obvious questions.
When you watch a popular science channel, you may see a random rainforest with a commentary“there are 122 tree species in this mountain forest in Honduras”. We may overlook it, but somebody had to climb up there and count those trees.
In our case, curiosity is required to spend a summer on roofs possessing so obvious handicaps: height, exposure to sun and wind, hard to reach with heavy equipments, not mentioning the various interactions with roof owners and managers who guard the gates of urban green roofs.
We believe it is cool to occupy ourselves with vacuuming bugs on green roofs. So, time to time we will return and give a better insight into our work.
Citation 1: the movie “Field of Dreams”, directed by Phil Alden Robinson, 1989
Citation 2: the movie “Casablanca”, directed by Mihály Kertész, 1942